Three-phase power is often supplied to a site of a residential or business consumer even when most or all devices at the site require only a single phase of the three phases. If there is a failure of one phase, three-phase devices are generally protected by three-phase relays which cut off all power to such devices. However, single phase devices may continue to operate if they are connected to operating phases. Devices that are connected to that phase that is lost become inoperative, even though the consumer continues to receive power from the other phases. The lost phase may cause inconvenience and economic loss.